The 1925 U.S. National Championships (now known as the US Open) was a tennis tournament that took place on the outdoor grass courts at the West Side Tennis Club, Forest Hills in New York City, United States. The women's tournament was held from August 17 until August 24 while the men's tournament ran from September 14 until September 19. It was the 45th staging of the U.S. National Championships and the fourth Grand Slam tennis event of the year.

Champions

Men's singles

🇺🇸 Bill Tilden defeated 🇺🇸 Bill Johnston 4–6, 11–9, 6–3, 4–6, 6–3

Women's singles

🇺🇸 Helen Wills defeated 🇬🇧 Kitty McKane 3–6, 6–0, 6–2

Men's doubles

🇺🇸 Richard Norris Williams / 🇺🇸 Vincent Richards defeated 🇦🇺 Gerald Patterson / 🇦🇺 Jack Hawkes 6–2, 8–10, 6–4, 11–9

Women's doubles

🇺🇸 Mary Browne / 🇺🇸 Helen Wills defeated 🇺🇸 May Sutton Bundy / 🇺🇸 Elizabeth Ryan 6–4, 6–3

Mixed doubles

🇬🇧 Kitty McKane / 🇦🇺 Jack Hawkes defeated 🇬🇧 Ermyntrude Harvey / 🇺🇸 Vincent Richards 6–2, 6–4